South Korean President Moon Jae-in's top security adviser returned home from the United States on Sunday after sharing the results of his recent visit to North Korea with Washington officials.

Chung Eui-yong, head of the National Security Office, went to the US capital with Suh Hoon, chief of the National Intelligence Service, last week to brief policymakers on his meeting with North Korean leader Kim Jong-un.

"Thanks to the support from the people, the two Koreas decided to hold a summit at the end of April, which will be followed by talks between the US and North Korea," Chung told reporters after arriving home.

Chung Eui-yong, head of South Korea`s National Security Office (R) answers questions at Incheon International Airport after returning from a trip to the United States on March 11, 2018. (Yonhap)

The advisor said he wished to praise Moon and Trump's devotion to seeking denuclearization and bringing peace to the Korean Peninsula. He also lauded Kim for making a "courageous decision."

"We will thoroughly push forward a diplomatic and administrative effort to successfully carry out the two summits," Chung added.

The two met US President Donald Trump on Thursday (local time) and conveyed Kim's willingness to meet the US leader. Trump and Kim had engaged in a heated war of words over Pyongyang's nuclear and long-range missile program, with each leader threatening to destroy the other side.

"This meeting won't take place without concrete actions that match the promises that have been made by North Korea," White House press secretary Sarah Sanders said earlier.

Sources, however, said Trump gave positive a response to the suggestion made by North Korea.

Chung and Suh are set to meet Moon after returning home from the US to discuss the details of North Korea's summits with Seoul and Washington.

Suh plans to visit Japan on Monday to share the outcomes of his visits to North Korea and the US, while Chung will go to China and Russia.

Chung will start his two-day trip to China on Monday and will then fly to Moscow, where he will meet his counterparts through Thursday. Whether he will meet Chinese leader Xi Jinping or Russia's Vladimir Putin, however, has not been decided.

Moon's special envoys met Kim on Monday last week amid the latest signs of reconciliation between the two Koreas, which technically remain at war, as the 1950-53 Korean War ended with an armistice not a peace treaty.(Yonhap)